Which lenses?

0ptics · Apr 23, 2012

Hello so I had some general questions about lenses, I'm a new photographer so I don't know much about them; so far I'm using the Nikon 18-55m (3.5-5.6) and 35mm (1.8).

1) Why are the prices on lenses so different when there is just a small different in their apertures, I hardly every go below f/2. eg. Nikon 50mm 1.4 (~$500) vs Nikon 50mm 1.8 (~$220)

2) How do you choose which lens to get? For an example if I wanted a zoom wide-angle, what makes one better than the other, Nikon 16-35mm f/4 (~$800) vs 14-24mm f/2.8 (~$2000)? The focal lengths are similar and they're both wide angle zoom lenses and other than build quality, weight, etc. how would you choose what's right for you? (For this question I'm referring to all lenses, I just randomly choose the 16-35mm vs 14-24mm)

3) I'm thinking about getting a prime portrait lens, is there a big difference in image quality/sharpness when it comes to the 35mm 1.8 (~$200) vs 50mm 1.8 (~$200) vs 85mm 1.8 (~$500)? Why does the 85mm cost so much more I thought the ONLY MAIN difference were their focal lengths.

4) I've always been told to use a prime lens for portraits, what makes it preferred than other lens such as wide angle, telephotos, even the 18-55mm?

5) What do they mean as FX cameras and DX cameras? Can FX cameras ONLY use FX lens and DX cams use DX lens?

Thanks for the help, I know they're basic question but I'm still kind of confused on why there are SO MANY lens and how do you pick the one for you?
0ptics

enzodm · Apr 23, 2012

1) "small" difference might be not so small (it's more than half a stop -obtaining large apertures while maintaining sharpness is not easy). However, the main reason for the difference of price is that, aiming at higher level, they build it better, with a better AF, with a better optical scheme, etc. Better optical scheme possibly gives better resolution (center and borders), less vignetting and CA, etc. Same reason why the same car may double the cost from the entry level to the top version. Plus, everything cost less if sold in larger quantities (like the 50/1.8, first approach to primes for many users).

2) If you can, you choose the focal length/lenghts you need, and the largest possible aperture according to your budget. The two zooms you mention cover different focal lengths (not very similar, although partially overlapping; and there is a stop more in the 14-24, even harder to get on a zoom). Since you already have a 18-55 and a 35mm, I would choose 14-24, if you need something like that for your kind of pictures.

3) go to Photozone and check image quality (and before that, try to develop an idea of what image quality is). However, in this case focal lengths are very different, so you do not choose by image quality, but according to the focal length you need. Full body portraits? Go shorter. Headshots/half body? Go longer. If you need an 85mm, you choose among 85mm lenses, not vs. 35mm. Why it costs more? There is more glass, and less people buy it (to simplify). Regarding focal length as "only" main difference, you do not obtain different focal length just by lengthening the lens (except for very simple optical schemes), so the difference might be not so small in terms of design and cost.

4) a prime lens may be as well a wide angle or a tele. You should compare prime vs. zoom. Try to find a zoom that goes up to f/1.4 or f/1.8

. Typically, a prime lens is easier to build (well) than a zoom, so you may have larger aperture, and better lens quality, including bokeh, spending less than a comparable zoom. So, it is not a rule. If you ask Canon users what they would buy for portraits, an answer would be 70-200/2.8 .

5) sensor size, APS vs. full frame. There is a lot of information around, just search for it. Of course, a lens made specifically for a smaller sensor may not cover the larger size of full frame. While the vice versa is not a problem.

Last question, how I choose? Budget. With no constraints, I would have a number of /2.8 zooms plus a number of f/1.4 primes. With budget constraints, I focus on the kind of pictures I want to take and choose accordingly. E.g., I bought myself a 50-150/2.8 used zoom for portraits.

PapaMatt · Apr 23, 2012

well, ENDOZM, gave you some very good advice, follow it and you will be do just fine.

djacobox372 · Apr 24, 2012

In the case of the nikon 50 1.8 vs. the 1.4, the optics on the 1.8 are actually better due to it being a newer design--the 1.4 is built a little better and has a couple more aperture blades which will improve bokeh when you stop down.

The prime lens arguments are mostly based on older zoom lens performance, modern pro quality zooms can rival primes, albeit at a much higher price.

sovietdoc · Apr 24, 2012

For zooms nowdays f/2.8 aperture is as good as it gets. Plus some zooms are more popular than others based on their working focal range and the quality of the picture. Usually 24-70 and 70-200s are considered "workhorses" for many. That already makes them expensive (for good quality glass) as everyone wants to shoot with one of those, and pair that high need/demand with lowest zoom aperture of f/2.8, and you got a zoom that "almost everybody wants"

Technically some photographers could easily get away with f4 or f5.6 zooms if they primarily shoot landscapes for example, but the manufacturers just like to throw everything in one package to charge more for "the best." So all their top optical developments go into f/2.8 zooms.

Except Canon who still doesn't want to add IS to 24-70 that costs 2300 bucks. They're probably saving IS for mark III of that lens, that they'll release later and charge 3500 bucks just because they can